Pacific Coast Highway

My wife and I are planning a vacation up the Pacific Coast Hwy. We're going to start in San Diego and end in San Francisco. We have a week to get as much in as possible. I'd like to spend 2 days in Frisco before we head back to Denver. As I've been researching this trip, I found that I'd like to see Yosemite and Death Valley if at all possible. I've never been to California so I don't know much about the distance from the coast to Yosemite and Death Valley and back. Is it even feasible for us to do the coast and the east or should we just stick to the coast part of the trip?

Time.

Hello and welcome to the RTA forum !

Does your week long trip include the time in SD and SF? If not you are going to be pushed for time and would be better off sticking to the coast. With 2 days in SF and at least 1, poss 2 in SD it would only leave you 3, maybe 4 days to travel the coast between the two as well as getting through LA.
If you have 7 days from SD and are spending 2 in SF you could, with your other 5 days, head to Yosemite for a night from Monterey/Castroville and spend a little time there before returning to SF which will probably take around 4 1/2 hours.
Time is not on your side I'm afraid but it could be done.

Sorry for forgetting to say that we're flying from Denver to San Diego and flying back to Denver from San Francisco. We get to San Diego on a Tuesday night and fly back to Denver on a Thursday night. We are going to rent a car for the drive and we already plan on staying in San Diego for 1 full day (Wednesday). On Thursday we are going to Catalina and staying overnight and returning to the mainland on Friday evening. We are staying with family in West Hollywood Friday night. That gives us 5-1/2 days to get in the rest of the trip. We would also like to get to San Francisco by Monday night so we could have 2-1/2 days there (Tuesday-Thursday). However, I'm open to changing things up a little if it makes for a more memorable vacation.

with those constraints

Well, its a good full 2 days to drive up the coast with exploration, so you don't have a lot of extra time to work with here. Since you've only got 3 days, I'd probably just spend that time along the coast and enjoy the time you have. With that 3rd day, you could do a quick drive over to Yosemite, but I suspect you may feel pretty rushed at that pace.

The other alternative if you want to do Death Valley and Yosemite would be to skip the coast and just drive to those 2 places. With 3 days, you could do a quick tour of those places and make everything work.

I figured that it would be a little tight to get all of that in. I think we're just going to stick with the coast. After I leave L.A. on Saturday evening, I think we're going to stay the night in Santa Barbara.

So, that gives me Sunday and Monday before I get to S.F. on Monday night. What are the recommended destinations for those two days up the coast. I'm sure there are a lot of things to see and do, but what are the "can't miss" sites?

Hearst castle.

A Hearst castle tour would be one of the highlights of such a trip along with the magnificent coastal drive through towns and around Big Sur. Unfortunately there has been disruption caused due to fires and is noted at Julia Pfieffer state park and Limekiln as two examples, although at Julia Pfieffer the fantastic sight of Mcway falls is still available from the trial.

I hope this isn't a stupid question, but does it matter where I start this trip? Is it better to go from SD-SF or SF-SD? The reason why I ask this is because I've been on numerous road trips in the past that got less interesting as we went further. Does it get better going north or going south?

Talked about options.

The most common reason for heading North to South is the fact that all the great ocean views and pull outs are on your side of the road so you won't have to cross traffic if you wish to stop.
The most common reason [it would seem] for going the other way is if the passenger is terrified of heights !